Why is that crab waving at me?


The big picture: Animal behavior
- Behaviors have a genetic basis
- allows evolution by natural selection
- Learning connects experience and behavior

Niko Tinbergen: Understanding animal behavior…
- Q1. What stimulus elicits the behavior, and what physiological mechanisms mediate the response?
- Q2. How does the animal’s experience during growth and development influence the response?
- Q3. How does the behavior aid survival and reproduction?
- Q4. What is the behavior’s evolutionary history?
Take home message:

Fixed action patterns
- Q1: stimuli that trigger behavior
- Tinbergen kept fish tanks with stickleback fish
- Males = red belly; Females= no red belly
- Male territorial behavior related to red color
- males also behaved aggressively when a red truck passed by!
- Fixed Action Pattern:
- developmentally ‘fixed’ → innate behavior
- trigger = sign stimulus (i.e. red color)

Environmental cues for behavior: Migration

- Environmental stimuli trigger and guide animal behaviors
- Birds, fishes, mammals (+ more) use cues to migrate long distances
- Why do animals not get lost in new habitats?
- Animals may use sun or moon position to navigate
- adjust route with circadian clocks!
Migration: What happens if it is cloudy?

Rhythm is gonna get you
- Animal behaviors often reflect biological rhythms
- circadian clocks or longer cycles
- Migration and reproduction cued by yearly seasonal cycles
- periods of day length and darkness
- Behaviors rhythms related to lunar cycles
- includes tides (e.g. crab reproduction, turtle nesting)

Forms of animal communication
- Stimulus may come from other animals (Q1)
- Signal:
- male waving claw at female crab
- Communication: transmission and reception of signals
- plays a role in primary cause (‘the How’)
- 4 common modes of animal communication
- visual, chemical, tactile & auditory

Fruit fly courtship
- Step 1: Male sees female and orients towards her
- uses olfactory chemical system to determine species
- Step 2: Male touches female with foreleg
- alerts female to his presence
- Step 3: Male vibrate wing in courtship song
- auditory behaviors tells female he is of right species
- If all communications are successful → sexy time

Forms of communication evolve with animal’s environment
- Many terrestrial mammals are nocturnal
- use olfactory and auditory forms
- usually are color blind
- Humans and most birds are diurnal
- use visual and auditory forms
- lack many chemical cues
- The amount of information communicated is variable
- read Honey Bee dance language in book

Experience and behavior
- Q2: How does the animal’s experience during growth and development influence behavior?
- What behaviors are innate and what are learned?
- cross-fostering & human twin studies

The capacity to learn in the animal kingdom
- Learning capacity → nervous system organization during development
- genome encoded
- finches can sing, but learn song from father
- Both nature (genes) vs nurture (environment)
- Learning Types: Imprinting, Spatial, Associative, Cognitive, Social

Landmarks (Spatial) + Trial and Error (Associative)


Trouble with assembling IKEA furniture? Call a crow…


Social learning in animals: root of culture


Evolution of foraging (Tinbergen Q3: Why?)
- Q3: How does the behavior aid survival and reproduction?
- Food behaviors: eating, searching, recognizing & capture
- how did foraging behavior evolve?
- Fruit flies: variation in an foraging gene (for) dictates larva travel when foraging
- forR (rover) vs forS (sitter)
- Which allele will be selected for in a population?

Evolution of mate choice (Tinbergen Q3: Why?)
- Mate choice and mating behavior influence reproductive success
- Seeking, attracting & choosing mates
- Evolution of parental care produces more viable offspring
- monogamy vs polygamy
- certainty of paternity
- Mate choice behavior leads to sexual and intrasexual selection

How have behaviors evolved (Tinbergen Q4)

- Behaviors have a genetic basis
- Courtship fruit fly: series of behaviors in male flies
- single gene (flu) controls entire ritual
- if flu mutated → no mating
- can be reversed in male and female!!!
- variation in gene → variation in behavior
- Variation in environment may cause behavior to evolve
Are all behaviors evolved to be selfish?
- Behaviors should be mostly selfish
- individual vs competitors
- Altruism:
- sterile male bees
- animals that vocalize warning calls
- Can unselfishness arise through natural selection?
- offspring survival: yours and relatives
- Inclusive fitness: increases genetic representation of related offspring
